1. Field of Invention
This invention relates to methods of taking physical inventory of goods in a store.
2. Prior Art
U.S. Pat. No. 4,419,734 discloses the standard approach to an inventory system by putting weight sensors in the stock selves. U.S. Pat. No. 5,235,559 discloses a method of using sound's standing waves to determine the thickness of a mass. However, this method doesn't use an absorption energy method. U.S. Pat. No. 4,812,887 shows how sound can be reflected & refracted thru a mass for determining the mass' thickness. Standing waves are not used in this method.